The overall goal of this application is to develop a safe, reliable, and biocompatible ventricular assist device (VAD) for toddlers/small children, between 15 and 35 kg (two to twelve years of age). Treatment options for this population, typically suffering from ventricular failure due to congenital and acquired heart disease, remain very limited in spite of the success of ventricular assistance in adults. The "Toddler VAD" (WAD) will utilize a centrifugal pump design with blood-lubricated bearings, optimized to minimize blood trauma and thrombosis. The device will be fully implantable, and capable of providing extended support (3 months). This project represents a collaborative effort between LaunchPoint, LLC, the University of Pittsburgh (UoP), and Children's Hospital of Pittsburgh (CHP). Collectively our consortium has a substantial expertise in cardiovascular bioengineering, computational fluid dynamics (CFD), blood damage modeling, control theory, electromagnetics, motor development, biocompatibility, and biorheology. We will specifically leverage technology and protocols accumulated through prior development of MedQuest HeartQuestTM and StreamLiner VAD to facilitate development of the TVAD. This application is further enhanced be the combined clinical experience of Drs. Robert Kormos, Bradley Keller, and Steven Webber who are internationally respected for pediatric cardiac care. This Phase-I project is scheduled for twelve months, and will culminate in three in vivo studies in juvenile sheep to demonstrate hemodynamic performance, safe operation, and basic biocompatibility. This will be accomplished through the flowing specific aims: Aim 1: Refine blood damage models using a novel blood shearing instrument (BSI) and state-of-the art biocompatibility assays. Aim 2: Design rotary blood pump with optimized hemodynamics utilizing CFD analysis and enhanced blood damage models. Aim 3: Fabricate and test TVAD prototype for pressure-flow measurement (H-Q curves), heat generation, and bearing performance. Aim 4: Conduct in vitro biocompatibility experiments with TVAD prototype. Aim 5: Conduct three short-term in vivo experiments to demonstrate basic hemodynamic performance and biocompatibility. Aim 6: Document Phase I feasibility to FDA standards. Our commercial partner, MedQuest Products (Salt Lake City, UT) is committed to collaborate with us through a subsequent Phase-II effort to ultimately bring this product to market.